1. Technical Field
The present invention generally relates to a vehicular drive shaft for transferring power in a motor vehicle. More particularly, the present invention pertains to a constant velocity joint used in conjunction with an aluminum propeller shaft in a driveline assembly.
2. Discussion
Most motor vehicles are equipped with a standard power train assembly including an engine, a transmission, a driveline assembly and driven wheels. A typical driveline assembly provides a power transfer path between an output shaft of the vehicle transmission or transfer case and the driving axle assembly. For example, the driveline of a rear wheel drive vehicle commonly includes a propeller shaft having a first universal joint for interconnecting the propeller shaft to the vehicle transmission and a second universal joint for interconnecting the propeller shaft to the drive axle assembly. In many applications, universal joints provide a suitable means for interconnecting shafts which rotate about non-collinear axes. However, certain power transmission applications require interconnecting shafts which rotate at angles closer to ninety degrees than standard universal joints commonly permit.
Depending on the vehicle""s suspension characteristics, the axle assembly may pitch and roll during vehicle operation. Specifically, relatively large articulations between the axle assembly and the vehicle frame occur when the vehicle is operated off-road or under maximum acceleration. Accordingly, because the engine and transmission are fixedly attached to the vehicle frame, the driveline assembly must provide the requisite degree of freedom to tolerate movement of the axle assembly relative to the vehicle frame. Unfortunately, a standard universal joint is not suitable for these applications.
In front wheel drive applications, a constant velocity joint is commonly implemented to interconnect the propeller shaft and the vehicle transmission at angles exceeding the operating range of universal joints. However, these applications usually include combining a steel propeller shaft with a constant velocity joint. While the use of steel propeller shafts has been tolerated in front wheel drive applications, a strong desire exists to implement aluminum propeller shafts in rear wheel drive vehicles. Specifically, a substantial weight reduction may be realized by implementing the lighter material in long rear wheel drive propeller shaft applications.
Unfortunately, difficulty arises when attempting to interconnect a typical constant velocity joint with an aluminum propeller shaft. Specifically, constant velocity joints commonly include steel radial mounting flanges at one end and an internally splined hub at the other end. Accordingly, to obtain the desired weight reduction and driveline function, the propeller shaft must mount to one of the constant velocity joint ends. A mount directly to the steel flange is improbable because dissimilar metals such as aluminum and steel may not be joined using conventional Metal Inert Gas (MIG) or Tungsten Inert Gas (TIG) welding techniques. In addition, a mount to the internally splined hub requires an externally splined shaft constructed from a material possessing sufficient torsional strength. While an externally splined aluminum shaft could be easily welded to an aluminum propeller shaft, aluminum does not exhibit the torsional strength required for use with the constant velocity joint.
Accordingly, it is an object of the present invention to provide a an aluminum propeller shaft with a constant velocity joint for use in rotational power transmission applications.
In the preferred embodiment, a driveline assembly for rotatably interconnecting a first power transmission device to a second power transmission device includes a propeller shaft, an adapter plate, a stub shaft and a constant velocity joint. The propeller shaft has a first end coupled to the adapter plate and a second end adapted to be drivingly coupled to the first power transmission device. The stub shaft includes a substantially cylindrical rod having a first end and a second end. The stub shaft further includes a flange radially extending from the first end of the rod wherein the flange is coupled to the adapter plate. The constant velocity joint is slidingly engaged and rotatably coupled to the second end of the stub shaft and the constant velocity joint is adapted to be coupled to the second power transmission device.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.